I. Technical Field
The present invention relates to end fittings for brake hoses and an improved hydraulic brake system utilizing manifold brake hose end fittings.
II. Brief Description of the Background Art
Hydraulic brake systems have long been used to provide braking for automotive vehicles. In vehicle braking systems, a hydraulic system functions as a control link between the operator's brake pedal, the master cylinder and the wheel braking mechanism. Braking mechanisms may include, for example, calipers for disc brakes or brake shoes for drum brakes.
The present invention is primarily concerned with the hydraulic system from the master cylinder to the brake mechanism located on the vehicle wheels. Hydraulic fluid transmits operator foot pressure from the master cylinder to the brake mechanism through steel tubing and reinforced rubber hose. The reinforced rubber hose is used to interconnect the rigid steel tubing segments of the braking system which are mounted to the chassis and either additional rigid steel tubing or brake mechanism parts which are mounted either to the axle or to the wheel hub.
Referring now to FIG. 4, a prior art braking system is shown schematically wherein a trunk line leads from the master cylinder to a point on the chassis adjacent the axle where it is connected to a flexible reinforced rubber hose which is connected on its other end to a separate tee fitting. The tee fitting is connected to two sections of rigid hydraulic tubing which extend in opposite directions along the axle toward each of the vehicle wheels. Each axle-mounted length of steel tubing is connected to the brake mechanism by means of an additional flexible, reinforced rubber hose.
An important consideration in the design of brake systems is the minimization of the number of "wet fittings". A "wet fitting" is a threaded connection between serially connected elements of the hydraulic brake line system. In vehicle assembly operations, wet fittings require careful assembly and subsequent testing to ensure the integrity of the hydraulic brake system. The great majority of leaks in hydraulic brake systems occur at wet fittings. Therefore, it is an objective when designing hydraulic brake systems to minimize the number of wet fittings. Flexible reinforced rubber hoses, referred to herein as brake hoses, have generally been used as links in a hydraulic brake system where there is relative movement between two parts, such as between the frame and an axle, between the frame and a wheel hub, or between the axle and a brake mechanism attached to a wheel. Brake hoses generally having fittings on both ends that are attached to the hose by a crimped connection which is capable of withstanding pressures up to 3,000 psi.
It is an objective of the present invention to provide an improved brake hose end fitting which functions as a manifold wherein a plurality of hydraulic fitting connections may be made in a single fitting.
Another object of the present invention is the provision of a brake hose end fitting of minimum outer diameter and incorporating one or more receptacles for receiving end fittings of tubing or other lengths of brake hose.
A further object of the present invention is to provide a brake hydraulic system wherein the minimum number of wet fittings are required thereby reducing manufacturing costs and improving reliability.
An additional objective of the present invention is to provide a method of assembling a brake hydraulic system wherein a manifold brake hose end fitting is used to interconnect a wheel brake hose to the chassis brake line and to a second portion of the hydraulic brake system which routes hydraulic fluid pressure to a second wheel.